The cells of bacteria contain DNA and RNA. When the bacteria are irradiated by deep ultraviolet (250-280nm), DNA and RNA will absorb a large amount of ultraviolet light, thus forming part of the isomers of m-diazobenzene (mainly composed of protease) and m-diazobenzene. This kind of substance can make the metabolism function of bacteria appear obstacle, and the continuous ultraviolet radiation, will cause the bacterial colony reproduction to be restrained and appear a large number of death. Its sterilization process is a physical destruction process, not affected by the environmental temperature, bacterial concentration, activity and other chemical equilibrium conditions, non-toxic, no residue, no odor, no by-products. As the cell walls and viral protein shells of all bacteria have no shielding ability to ultraviolet rays, ultraviolet rays cause uniform damage to DNA and RNA, and there is no need to change drugs or use combination agents. It is especially suitable for disinfection of air, water and surface of objects.

Stethoscope is the most widely used medical equipment in the world. The lack of effective sterilization and disinfection treatment for stethoscope will provide a favorable living environment for bacterial viruses, and is a potential source of malignant transmission of some infectious diseases. Based on the important application prospect of deep ultraviolet LED in disinfection and sterilization, it has been widely concerned by the medical community. Many scholars have gradually listed the deep ultraviolet LED as the first choice of sterilization and disinfection of stethoscope. Recently, the prototype of portable UV-LED sterilized stethoscope has come out, which includes the most advanced UV-LED light source. The ultraviolet light emitted will automatically disinfect the stethoscope membrane. At the same time, Kruskal Wallis method was used to evaluate the disinfection effect of UV-LED: the experiment proved that the bacteria amount on stethoscope membrane was reduced by 90% after UV-LED irradiation for one minute. Therefore, UV-LED is an effective sterilization scheme for stethoscope membrane, and it is portable and wearable, which has a great application prospect.